Preparation of substituted



wherein u R represents analkyl Un wd Saws.

PREPARATION or SUBSTITUTE-1'5 QX ZPP DONE? .Arthur B. Steele, Ossining, N- Y., ass ignor toxUnionCar- 3 bideCorporafion, a corporation of New York I H No Drawing. Application November 6,1956

oxazolidones and to a process for preparing them. More particularly, this inventionfisfdirected to a process for obtaining certain oxazolidones containing alkyland hydroxyalkyl'substituents obtainedby. the reaction of carbon dioxide and an aliphatic secondary amine corresponding to the formula: Y 1

- ITO-(1H H or hydroxyalkyl group such as methyl, .ethyl, butyl, Z-hydroxyethyl or a 2 hy droxypropyl group. 1'

,Heretofore, studies have indicated that carbon dioxide 4 and ethanolamines in which the amine group is second- ,ary are converted ,at elevatedte'mperatures and pressures to'the corresponding N,N'-disubstituted'piperazines. This process of synthesisis disclosed and,,claimed in my copending application Serial "No; 463,330, 'filedAugust '27, 1953, entitled Process 'forthe Production'of Substituted Piperazines. It has beenfound thatsubstituted piperazines are'not formed 'uponireacting isopropanolamines,

containing at least one2-hyd'roxypropyl group with .carbon dioxides at elevated temperatures and pressuresxfIn.- stead; there are formed -3-alkyl'and 3-hydr'o xyallgyl-5 methyloxazolidones as the main, if not thesole, products.

The reaction thatitakesplacecan be illustratediby an equation as follows:

BNHOHzCHOHOHa-lco. R -N o +1120 Theprcess of this invent on s carried out at elevated temperatures and under superatmospheric pressures. It has been found that temperatures in the range offrom 120 C. to 175 C. and superatmospheric pressures in the range of from 175 to 700 pounds persquare inch absolute provide satisfactory yields of product and high efiiciency. The pressure desired for the reaction may be themes sure'gwhich is derived mostly from the heating of the reactant amine carbonate salts in a closedreaction vessel or the pressure can be an externally appliedpressure wherein Rjis as above defined. 0

derived from the imposition of any other gas such as carbon dioxide or nitrogen, over the reactionmedium. Asa matter of practical convenience,.however, it is preferred to charge analiphatic secondary amine containing at least one 2-hydroxypropyl group to an autoclave and pressure with carbon; dioxide; to.- efiect-the pressure de sired. A

e 2,868,801 "LC?- we ..J 88

Incarrying outthe process of this invention, an aliphatic secondary amine containing at least one 2-hydroxypropyl group is employed either undiluted or diluted with suitable solvents such as water or diethylene glycol. Water is a preferred solvent because of its low cost, ease of removal from the reaction product, and its solvent power for both reactants and products. In the presence of water, ,where water-is theonly. diluent, or water is a minor component of the total diluent, the simple carbonate salt of the substituted isopropanolanrine is formed. In the absence of water, addition 'of carbondioxide to the secondary amineresults inthe formation of the carbamic acid salt. i

The ratio of carbon dioxide to amine is not a critical feature ofthe process. Since the formation of the oxazolidone structure" requires the reaction of equimolar quantities of the substituted isopropanolamine and carbon dioxide, less than equimolar amounts of carbon dioxide in,;the:reaction system will -reduce,"proportionately, the product yield.

The novel 3-hydroxyalkyl substituted S-methyloxazoliidones can be characterized by the general formula:

- Ca on-gum as aZ-hydr'oxyethylor Z-hydroxypropyl group. i

, It has been discovered that 3-(hydroxyalkyl)-5-methyloxazolidones are commercially valuable as la: selective solvent for the separation of aliphatic-aromatic hydrocarbon mixtures." For example, it has been foundtha't aliphatic-aromatic hydrocarbon mixtures canbe advantage'ously separated intofractions which difler in' their degree of aromati'city, that is, into more aromatic and less aromatic fractions. The 3-(Z-hydroxyalkyl) 5-meth yloxazolidones can be furtheremployed to separate hy drocarbon mixtures of-the type described into a multi plicity of fractions having different properties and, lastly, 'the'y' can be'employed to separate anaromatic hydrocar bon, in a pure form from admixture with other hydroear: bons. Theprocess of employing ..3-(2-hydroxyalkyl) -5- methylo'x'azolidone-Z is'described and claimed in copend ing application of A. B."Steele, J. BL; ONeal and 1 1R.

Anderson, SerialNo. 555,874, filed December 28,1955; entitled Solvent vQl-Ex'tr'atcti'on.Using Substituted Oxaz i; dones. I I The following examples will serve to i11u 8rat practice of the invention:

I ;,E A ,R E Preparation of 3 2 hydrbiypropyl) 5-niezhyioxtzauli done-2 Y nant. The amine was removed by slurrying the distillate with cation exchange resin and the product'redistilled to provide material characterized as 3-(2-hydroxypropyl)-5- methyloxazolidone-Z on the basis of the following physical and chemical properties:

Boiling point, C 132-133 at 0.2 mm. Specific gravity at 20/20 C 1.1398. Refractive index, 20 C 1.4690. Molecular weight, by saponification:

Found 159. Calculated 159.2. Physical state, 25 C Viscous, water-white liquid. Nitrogen content, by Kjeldahl method:

Found 8.8pe'rcent. Calculated 8.8 percent.

A product yield of 75 percent was obtained; unreacted diisopropanolamine being recovered quantitatively.

EXAMPLE II Preparation of 3,5 dimethy xaz0lid0ne-2 Into a stainless steel pressureautoclave were charged 292 grams (3.28 moles) of N-methylisopropanolarnine as a 25 percent solution in water. The carbonate salt of the amine was formed by saturating the solution with carbon dioxide to a constant pressure of 160 pounds per square inch (gauge) and was converted to oxazolidone by heating at 160 C. and 600 pounds per square inch pressure for 24 hours. The crude make was cooled to25f C., discharged into'a laboratorystilL andtractionally distilled to recover 6 0 grams of u nconverte d N-methylisopropanolamine and 240 grams of crude 3,S-dimethyloxazolidone-Z which was contaminated with approximately 3.9 percent N methylisopropanolamine, as determined by titration with standard acid. The amine was removed by-slurrying the crude product with cation exchange resin (Rohm and Haas IR11 2) which had been prepared for the hydrogen cycle by treating with dilute sulfuric acid. A 3-minute contact of the resin was adequate to remove last traces ofthe amine.

The resin was recovered by filtration and the-filtrate i carefully distilled to provide a pure sample of 8,5-dimethyloxazolidone-Z characterized by the following properties:

Physicalstate, 25 C Colorlessliqnid.

Odor

M ld- Boiling point, C 92 at 1.5 mm.

Specifi'chgravity, /26" e.-. r039. Refractive index, (n 21 C.) '1.4464.

Nitrogen content, percent by weight:

Found 12.08. Calculated 12.15. Yield, based on N-Methylisopropanolamine:

Crude product 63 percent. Refined product 58 percent.

EXAMPLE III Preparation 0 3-ethyl-S-methyloxazolidone-Z sure absolute and characterized by the following properties:

Physical state, 25 C Colorless liquid.

Odor Mild. Boiling point, C 87 at 1 mm.

Specific gravity, 20/20 C 1.057. Refractive index, (n 21.2 C.) 1.4458.

.Nitrogen content, percent by weight: I

Calculated 10.82. Found 10.8.

Although an accurate yield value could not becalculated due to a ruptured line which resulted in the loss of an undetermined amount of the charge'to the autoclave, recovery of refined product'was approximately percent, based on the Weight of N-ethylisopropanolamine charged to the unit. 5

EXAMPLE IV I Preparation 0 3-bzttyl-5-methyloxazolidone-Z The carbonate salt of .N-butylisopropanolamine in water solution [350 grams (2.67moles) of N-butylisopropanolamine in 1100 grams of water] was heated in a stainless steel autoclave at 155-160" C. under pressure of 500-520 pounds per square inch(gauge) 'for' 24 hours. Upon discharging the bomb, it"was noted that the crude make had separated into two liquid phases. The oil layer was recovered and the aqueous layer extracted with benzene; thecrude product fraction and the extract were combined'prior to distillation. Approximately 250 grams of crude 3-butyl-5-methyloxazolidone 2-,'boiling in the range of 105-108 0. at 1 mm. of Hg pressure absolute, were recovered. The product fraction was freed of a small amount ofamine contaminant by treating the oxazolidone in aqueous Physical state, 25 C Colorless liquid.

Specific. gravity, 20/20 'C 1.009. Refractive index (n 21.2"

c.)' 1.4482. Nitrogen content, percent by weight: V

Calculated 8.92. Found 8.88.

Yield of crude -3-buty1+5-methyloxazolidone-2 was 60 percent of the theoretical yield, based on N-butylisopropanolamiiie; yield of refined product, 48 percent.

' -What is claimed is: I

1. A process for the production of substituted 'oxazoliclones which comprises reacting an aliphatic secondary amine containing at least one 2-hydroxypropyl group and carbon dioxide at an elevated temperature in the range of from C. .to C. under'a superatmospherie'pressure in the range of from175 to -700'pounds per square inch absolutej l J 2. A process for the production of 3,5-dimethyloxazolidone-Z which comprises reacting N-methylisopropanolamine and carbon dioxide at an elevated temperature in the range of from 120 C. to 175 'C. under a superatmospheric pressure in the range of-from 175 to 700 pounds per square inch absolute. i

3. A process for the production of 3-(2-hydroxypro- .pyl)-5-methyloxazo1idone-2 which comprises reacting diisopropanolarnineand carbon dioxide at anelevated'te'inperature inthe range "of fronilZO C. to 175 C: under a superatrnos pheric pressureinthe range of from 175'to 700 pounds per'squ'a'r inch absolute.

4.' A process for the production of 3-butyl-5 methyloxazolidone-2 which comprises reacting N-butylisopropanolamine and carbon dioxide at an elevated temperature in the range of from 120 C. to 175 C. under a superatmospheric pressure in the range of from 175 to 700 pounds per square inch absolute.

5. A process for the production of a 3-alkyl-5-methyloxazolidone-Z which comprises reacting secondary aliphatic amine containing at least one 2-hydroxypropyl group and carbon dioxide at an elevated temperature in the range of from 120 C. to 175 C. under a superatmospheric pressure in the range of from 175 to 700 pounds per square inch absolute.

6. A process for the production of alkyl and hydroxyalkyl substituted oxazolidones which comprises reacting a secondary aliphatic amine corresponding to the formula:

wherein R represents members selected from the group consisting of lower alkyl and lower hydroxyalkyl groups and carbon dioxide at an elevated temperature in the range of from 120 C. to 175 C. under a superatmospheric pressure in the range of from 175 to 700 pounds per square inch absolute.

7. A process for the production of alkyl and hydroxy alkyl-substituted oxazolidones which comprises heating a reaction mixture comprising carbon dioxide and a secondary aliphatic amine corresponding to the formula:

wherein R represents members selected from the group consisting of lower alkyl and lower hydroxyalkyl groups at an elevated temperature in the range of from 120 C. .to 175 C. under a superatmospheric pressure in the range of from 175 to 700 pounds per square inch absolute.

8. A process for the production of alkyl and hydroxyalkyl-substituted oxazolidones which comprises heating a reaction mixture comprising carbon dioxide and an aqueous solution of a secondary aliphatic amine corresponding to the formula:

wherein R represents members selected from the group consisting of lower alkyl and lower hydroxyalkyl groups at an elevated temperature in the range of from 120 C. to 175 C. under a superatmospheric pressure in the range of from 175 to 700 pounds per square inch absolute.

9. A process for the production of alkyl and hydroxyalkyl-substituted oxazolidones which comprises heating a reaction mixture comprising carbon dioxide and a di- 6 ethylene glycol solution of a secondary aliphatic amine corresponding to the formula:

wherein R represents members selected from the group consisting of lower alkyl and lower hydroxyalkyl groups at an elevated temperature in the range of from C. to C. under a superatmospheric pressure in the range of from 175 to 700 pounds per square inch absolute.

10. A process for the production of alkyl and hydroxyalkyl-substituted oxazolidones which comprises heating a reaction mixture comprising carbon dioxide and a diethylene glycol-water solution of a secondary aliphatic amine corresponding to the formula:

CHrCH-CHz-N-R wherein R represents members selected from the group consisting of lower alkyl and lower hydroxyalkyl groups at an elevated temperature in the range of from 120 C. to 175 C. under a superatmospheric pressure in the range of from 175 to 700 pounds per square inch absolute.

11. A process for the production of alkyl and hydroxyalkyl-substituted oxazolidones which comprises reacting carbon dioxide and a secondary aliphatic amine containing at least one 2-hydroxypropyl group to form a reaction mixture containing the carbamic acid salt corresponding thereto, and heating said reaction mixture at an elevated temperature in the range of from 120 C. to 175 C. under a superatmospheric pressure in the range of from 175 to 700 pounds per square inch absolute.

12. A process for the production of alkyl and hydroxyalkyl-substituted oxazolidones which comprises reacting carbon dioxide and an aqueous solution of a secondary aliphatic amine containing at least one 2-hydroxypropyl group to form a reaction mixture containing the carbonate salt corresponding thereto, and heating said reaction mixture at an elevated temperature in the range of from 120 C. to 175 C. under a superatmospheric pressure in the range of from 175 to 700 pounds per square inch absolute.

References Cited in the file of this patent UNITED STATES PATENTS 2,399,118 Homeyer Apr. 23, 1946 2,755,286 Bell et al July 17, 1956 2,773,067 Viard Dec. 4, 1956 FOREIGN PATENTS 913,163 France May 20, 1946 Patent No. 2,868,801

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION January 13, 1959 Arthur B. Steele It is hereby certified that error appears in the -printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5 lines 16 to 18, claim 6, lines 291:0 31, claim 7, lines 41 to 43, claim 8,- column 6, lines 3 to 5, claim9, and lines 16 to 18 claim 10, the formula, each occurrence, should appear as shown below instead of as in the patent:

(3H -cH-cH -N-R Signed and sealed this 19th day of July 1960. (SEAL) Attest:

KARL :AXLINE ROBERT c. WATSON Commissioner of Patents Attesting Officer 

1. A PROCESS FOR THE PRODUCTION OF SUBSTITUTED OXAZOLIDONES WHICH COMPRISES REACTING AN ALIPHATIC SECONDARY AMINE CONTAINING AT LEAST ONE 2-HYDROXYPROPYL GROUP AND CARBON DIOXIDE AT AN ELEVATED TEMPERATURE IN THE RANGE OF FROM 120* C. TO 175* C. UNDER A SUPERATMOSPHERIC PRESSURE IN THE RANGE OF FROM 175 TO 700 POUNDS PER SQUARE INCH ABSOLUTE. 